This is the second of three lectures directed at laying a basis for the development of diplomatic doctrine. It deals with diplomacy as the tactics of foreign relations. The preface to this series and the first lecture in it set out some thoughts on diplomacy as strategy. The third lecture will consider diplomacy as risk management.

In American foreign policy, perpetual warfare, arms races, economic bullying, and derogatory rhetoric seem for the time being to have supplanted diplomacy. This is a profoundly destabilizing approach to foreign relations. Once it has run its course, Americans will need to rediscover, reconstitute, and rebuild diplomatic capacity.

Our objective in doing so should be to train and field diplomats who are as skilled in the profession of persuasion as our military are in the profession of arms. The extent to which we are able to draw on diplomatic doctrine – guidance for the application of judgment to trends, events, and opportunities – will determine the speed and effectiveness with which we can accomplish this. We need to work now on developing such doctrine for application to our foreign policies and practices when that is possible.

Diplomacy is an instrument of statecraft that few Americans have been educated to understand and whose history – even in relation to our own country – most do not know. Diplomacy emphasizes peaceably arranged change, but it is not pacifist. Diplomacy is how power persuades states and peoples to accommodate adjustments in relations they instinctively disfavor. It uses words to portray capabilities and convey intentions in order to shape the calculus of foreign partners and opponents and cause them to make desired changes in their policies and behavior.

Diplomacy is the verbal tactics of foreign relations. It is the alternative to the use of force as well as its prelude, facilitator, and finale. It is both the implementer of policy by measures short of war and the translator of the results of war into durable outcomes.

Americans celebrate our independence on the day of its official declaration, July 4, 1776. Most imagine that we achieved our autonomy then or on October 19, 1781, when we (and the French) defeated the British at Yorktown. But this ahistorical view disregards the essential role of diplomacy in such adjustments of relations. U.S. separation from the British Empire was only secured when the British conceded it. It took John Adams, Benjamin Franklin, John Jay, and Thomas Jefferson nearly two years to persuade the British to accept that the necessary consequence of their military defeat was American independence. This became a legal reality only on September 3, 1783, when Britain and the United States signed the Treaty of Paris.

The failure of Americans to recognize the centrality of diplomacy to war termination, including in our own war of independence, is not inconsequential. Recall the ludicrous triumphalism of President George W. Bush after the defeat of the Iraqi Army in 2003, when he stood on an aircraft carrier under a banner, reading “Mission Accomplished.” Subsequent events in Iraq provided a costly reminder that no war is over until the defeated admit defeat and accept its consequences. Such adjustments do not happen automatically. They are achieved through diplomacy or not at all.

The tragic American experience in Iraq was also a reminder that to achieve peace, there must be a leader among the defeated populace with the authority to commit them to it. This is why the United States left the Japanese emperor on his throne after World War II. The failure to consider, let alone address, the question of who might be able to commit Iraqis to cooperation with their foreign occupiers – and what would be required to persuade Iraqis to do so – accounted in no small measure for the anarchy that followed the removal of the Saddam regime in Baghdad.

Diplomatic tactics for war termination are an essential element of any war strategy. But the translation of military triumph into political victory is a task that the American way of war all too often omits. This reflects a history of pursuing the annihilation of enemies, their unconditional surrender, and their political reconstruction through occupation. Disdain for diplomacy that negotiates postwar adjustments in relations, together with “mission creep,” is a major reason that so many American wars spin on without end or abate, only to resume in altered form.

Most Americans seem to see diplomacy and war as a discontinuous dichotomy. But diplomacy does not halt when war begins. Nor does the role of military power end when peace replaces war. Effective diplomatic communication is essential to escalation control. It is also necessary to convince enemies to make concessions that justify ending wars with them on agreed terms.

War is the pursuit of policy through violent coercion up to and including mass murder. It does not supplant the need to pursue policy by other means. Enemies must be made to see that it is in their interest to agree to terms rather than to suffer devastation or annihilation. This makes diplomatic communication more important than ever in times of war. One should never lose contact with the enemy on the battlefield or at the negotiating table. Even when the objective of war is unconditional surrender – generally, a counterproductive posture that incentivizes maximum resistance by the enemy – diplomacy is important to lay the basis for the postwar order. It is not the military end state that vindicates strategy, it is the political end state.

For wars with limited objectives to end, the combatants must be able to end their combat through a negotiated resolution of differences on terms they consider acceptable. The fact that they are fighting makes it all the more important that they talk. This consideration is why the Chinese – contrary to Western practice – wisely left their embassies in place during their conflicts with both India and Vietnam. The need to preserve the negotiability of differences is also why Bismarck counseled that one should be polite even when conveying a declaration of war.

Diplomacy in the run-up to war and during it serves to prevent still other adversaries from becoming enemies, to preclude the formation of hostile coalitions, to deny alliances to adversaries, and to divide enemies from their allies and partners. Wartime diplomacy works to bolster one’s own alliances and partnerships, to extract concessions from actual and potential belligerents, and to lay the groundwork for order and stability to succeed mayhem. Far from ending during warfare, diplomacy complements military operations and enables them to fulfill their political purposes. It is how the warring parties translate the results of their combat into adjustments in relations between them.

As important as diplomacy is to the fruitful conduct of war, it is also the principal and most effective alternative to it. In some respects, diplomacy can be likened to ju-jitsu [柔术] – the use of an opponent’s energy, strength, desires, preconceptions, and mode of coercive action to match, misdirect, disarm, and counter him. Success depends on knowing what one wants, understanding one’s opponents’ preoccupations, being prepared, seeing one’s objective through one’s opponents’ eyes as well as one’s own, exemplifying stamina and resilience, and knowing when to exploit openings as they appear.

For the most part, Americans have not thought about the role of diplomacy in the expansion of the United States to its present borders. Some of the diplomacy that built America was peaceful. Some involved financial transactions. Some represented the translation of military success into territorial adjustments and other concessions. American diplomacy opportunistically exploited strategic calculations on the part of the foreign nations with which the United States was negotiating to make America great. Here are a few examples.

In 1802, President Thomas Jefferson authorized James Monroe and Robert Livingston to try to buy New Orleans and Florida from France for up to $9.375 million. Napoleon had just suffered a dispiriting defeat in Haiti and written off French colonial ambitions in the Western Hemisphere. He needed money. On April 11, 1803, Napoleon unexpectedly offered to sell the United States all of France’s remaining territories in North America.

Without waiting for further instructions, Monroe and Livingston set about negotiating a treaty purchasing France’s “ Louisiana” territory for $11.25 million, plus the forgiveness of $3.75 million in French debt. It took them two weeks to reach agreement with the French. Their opportunistic diplomacy peacefully doubled the size of the United States at a cost of about 3 cents an acre. (Had Americans tried to take this territory by force rather than diplomacy, we could have succeeded, if at all, only at vastly greater expense in treasure as well as blood.)

In 1844, President James K. Polk was elected on an aggressively expansionist platform. At the time, the border between the United States and British Canada west of the continental divide was in dispute. Polk threatened to go to war with Britain over the issue. Negotiations between his secretary of state and the British envoy to Washington began in the summer of 1845. Britain made a deliberate decision to appease the United States rather than entrench a hostile relationship with it. In 1846, the two sides concluded the “Oregon Treaty.” This confirmed U.S. sovereignty south of the 49th parallel everywhere but on an undivided Vancouver Island.

Polk’s diplomatic success enabled him to turn his combative attention to Texas. In 1846, he provoked war with Mexico. In the negotiations that followed the U.S. Army’s victory, the United States insisted on maximum terms from Mexico, softened by financial inducements. The resulting Treaty of Guadalupe-Hidalgo, signed on February 2, 1848, ended Mexican resistance, resigned Mexico to the U.S. annexation of Texas, and compelled it to sell California and the rest of its territory north of the Rio Grande. In 1853, the U.S. ambassador to Mexico, James Gadsden, was able to buy additional territory from a still-intimidated Mexico through which to route a southern transcontinental railway.

In 1859, Russia offered to sell Alaska to the United States, hoping that this would position Americans to counter British power in the North Pacific. The U.S. Civil War intervened. But, in 1867, Secretary of State William Seward took up a renewed Russian offer and was able to arrange terms for the territorial transfer. The U.S. acquisition of Alaska ended Russia’s presence in North America and ensured American access to both the Pacific’s northern rim and the Arctic.

In normal times, diplomacy is not concerned with redefining frontiers but with arranging and policing the terms of trade, investment, and other citizen and corporate interactions across borders. The first treaties American diplomats negotiated were “treaties of commerce and navigation.” These were bilateral agreements designed to outflank British and other colonial mercantilism. They typically ensured “most favored nation” treatment with respect to trade, enshrined “national treatment” and prohibited discrimination, offered access to local courts or arbitration tribunals, exchanged consular officers to promote trade and investment and protect citizens, and established the rules for commerce and shipping in times of war.

Sixty-three such treaties remain in force in the United States today, despite the late 20thcentury replacement of their primitive bilateral regulation of trade and maritime commerce with the more sophisticated and efficient multilateralism of the World Trade Organization (WTO) and the U.N. Convention on the Law of the Sea. These and other treaties define the multilateral framework of globalization from which the Trump administration is now withdrawing the United States. The American abandonment of multilateral trade and investment diplomacy, combined with aggressive protectionism that ignores previously prevailing norms, foreshadows future U.S. isolation and irrelevance in global economic governance.

Other major trading nations show no interest at all in replacing multilateral institutions and the globalized economy they regulate with new bilateral arrangements with the United States or each other. On the contrary, they are going ahead with new multilateral schemes that bypass or exclude the United States. Examples include the Japanese-led revival of the Trans-Pacific Partnership, the Regional Comprehensive Economic Partnership (RCEP), burgeoning arrangements under China’s Belt and Road Initiative, and policy harmonization and standard setting under the Paris Climate Change Accord. Future American administrations will find themselves on the outside of these arrangements, trying to get in. Resentment of American unilateralism is replacing allegiance to U.S. leadership. Readmission to the councils of governance in an order that has been redefined without U.S. input will demand an unprecedented level of American diplomatic skill.

It is not new for the United States to exempt itself from global norms. What is new is the relative decline in American power in relation to others and the norms they have accepted. As an example, the United States is now the only country not to use the metric system. This ensures that American products cannot meet the standards of foreign markets without redesign or conversion.

This difference has not been much of an impediment for the U.S. economy, given its size, dynamism, and ability to print dollars instead of exporting goods and services to pay for imports. But, as the U.S. absents itself from multilateral institutions, others will see an opportunity to use differences like this to their competitive advantage. (I have personally seen American industry lose billions of dollars in markets abroad to the combination of U.S. complacency and foreign exploitation of standard setting to exclude the import of U.S. products.) In a globalized world, lack of alertness to such issues soon makes one uncompetitive.

The pseudo-populist plutocrats of the Trump administration came into office asserting that the open world economic order that successive previous administrations had fostered was unfair and had victimized American workers. The United States has now set the rules it created and enforced for so many decades aside. This is not just isolating America, it is severely undermining global order and governance. Meanwhile, alliances are becoming conditional, transforming themselves into ententes. Protectorates are decoupling themselves from their protectors, as confidence in the reliability of their security guarantors wanes. Client states are cynically abandoning allegiances and repositioning themselves between patrons. New trade pacts are coalescing even as other, more inclusive regimes cleave asunder. In the new world disorder, survival amidst prosperity will demand proficiency in the tactics of diplomatic maneuver.

If the key to sound strategy of any kind is whether one is asking the right question, the key to sound tactics is to ask “and then what?” before taking action. Strategy must be set at the top but tactics are best driven from the bottom up and from the field in. Those on the front lines are best positioned to judge the most effective tactics for pursuing strategic objectives in the circumstances they face. But the current trend is toward the centralization of American decision-making in Washington, the substitution of deductive reasoning from ideological presuppositions for inductive reasoning, and the disparagement of expertise and experience.

Often this sort of “narcissistic policy disorder” – to quote George Will – results in resort to attempted economic coercion through sanctions. Sanctions are politically attractive. They sever relationships and unravel ties that bind parties together. The immediate damage they do is regrettably almost always reciprocal. Groups and activities on both sides suffer. But the pain usually falls directly on parts of the private sector and very indirectly on the public at large – not at all on the politicians demanding punitive action or on the government of which they are part. Thus, sanctions are effective political theater even if they almost never work. There are numerous reasons for this.

The first is the nature of economic power. Unlike military power – which persuades by menacing the life, liberty, and happiness of those to whom it is applied – economic ties draw their power from the gains nations, companies, and individuals make from exchanging what they have for what they don’t. Like a string, economic power connects peoples, companies, and individuals and enables them to pull each other together. It induces cooperation through mutually beneficial trade and investment. This makes economic measures ideal tools of any strategy aimed at building communities or other cooperative international relationships, as the political effects of removing trade barriers in the European community or the growth of the Sino-centric supply-chain economy in East Asia both illustrate. But the fact that economic power links and encourages rather than sunders or discourages profitable exchanges of goods and services between nations also makes economic power a very poor tool of coercion. You can pull on a string. You can’t push on it.

Second, sanctions can be essential bargaining chips to be traded for concessions by their target. But this requires that they be part of a negotiating strategy, not a punitive end in themselves. At the bargaining table, sanctions are useful as threats. The fear of sanctions, the precise effects of which can seldom be modeled with accuracy, is generally more compelling than their actual effect. If sanctions are in fact imposed, their only utility becomes their removal in exchange for concessions that are part of a deal. But the longer sanctions are in place, the more difficult they are to remove.

Third, once sanctions are put in place, two things routinely happen. Their efficacy begins to be measured not by their effect on the policies and behavior of their target but by the pain they are seen to inflict on it. Their original purpose of compelling changes in behavior by their target is effectively forgotten. While the politicians grandstand, markets quickly adjust to the distortions in supply and demand that sanctions create. The government that is the object of the sanctions engages in import substitution, finds other suppliers, and institutionalizes smuggling to meet the demand for whatever it has been deprived of. This is good for its domestic industry, the economic competitors of the power imposing sanctions, and the profits of organized crime.

Fourth, as new patterns of commerce set in, some in the country imposing sanctions come to count on the protection from foreign competition that sanctions afford. As an example, consider the opposition of American sugar producers to the lifting of sanctions that preclude Cuba, which is a much lower cost sugar producer, from selling sugar in the United States. Some in the target country or in third countries also acquire a vested interest in the continuation of sanctions. Consider the growth of the armaments and other industries under sanctions on apartheid-era South Africa or the emergence of Brazil as an alternative source of soybeans for Japan and other importers after the Nixon administration restricted their export in 1973.

Fifth, like war – for which it is spuriously touted as a substitute – sanctions punish but do not automatically translate into changes in policy or behavior on the part of their target. Ostracism does not persuade, it enrages. Unacceptable demands are not made acceptable by maximum pressure and attempted public humiliation unaccompanied by a credible negotiating process. Nations are at their most dangerous when they perceive an existential threat or an injustice from which there is no potential relief through diplomatic dialogue. Japan reacted to such sanctions with a desperate attack on Pearl Harbor.

Finally, even when integrated into a negotiating process, sanctions increase public pressure but thereby encourage resistance, exacerbate recalcitrance, facilitate shifting the blame for everything going wrong domestically to those imposing them, rally nationalists against perceived foreign bullying, and make compromise more rather than less difficult. So sanctions typically retard rather than speed agreement at the negotiating table. In the end, as the Iran nuclear non-proliferation deal illustrated, the only utility of sanctions is their removal. This can seldom produce a deal resolving the dispute that justified them, but it can serve as a bonus to one.

In the new world disorder, the American advantages that once gave unilateral U.S. sanctions their unique impact are disappearing. In 1950, the United States provided 16.7 percent of the world’s exports and took a whopping 81 percent of its imports. In 2016, these figures had fallen to 9.1 and 13.8 percent, respectively. A disproportionate percentage of American exports now consist of financial and other services for which there are an increasing range of alternative non-American sources. This makes America a very powerful but no longer dominant force in international trade and investment. Americans have fewer followers internationally and a declining ability to impose economic and financial isolation on our foreign adversaries.

In these circumstances, the United States, as the issuer of the principal currency for settling international transactions, has come to rely on its sovereignty over the dollar to block trade and investment with countries like Iran, north Korea, and Russia. But this effectively imposes U.S. policies to which they object on economic powers like China, India, Japan, and south Korea. As these countries see it, the United States is abusing its power as the issuer of the preeminent global currency. This is driving them to explore work-arounds and substitutes to the dollar in their own trade with countries under U.S. sanctions. If they succeed, the consequence for Americans could be a catastrophic loss of the “exorbitant privilege” of printing money to pay for imports that we have long enjoyed. In any event, current trends guarantee that future generations of American diplomats will have less financial coercive power to work with. This will test their negotiating skills in ways that previous generations have not experienced.

Diplomatic negotiation is a teachable art. It differs from negotiation in other contexts because it takes place between nations, not citizens subject to coercion by the sovereign authority of their government through litigation in its courts. The participants in diplomatic negotiation have the option of resorting at any time to the use of force against each other. They can choose to accept or ignore the prevalent norms and rules of international law. Implicit agreement on rules by one side cannot assure that the other side will adhere to them. If diplomatic negotiations fail, the result is protracted impasse, escalating tensions, or armed conflict, not a lawsuit leading to a court decision and penalties. The stakes in international negotiation are higher than those in domestic transactions. All the more reason to demand excellence from those charged with conducting it.

Diplomatic negotiation should be viewed as an application of national power by measures short of war. The object is to persuade one’s opponent to embrace the need to accommodate one’s demands, faute de mieux. The purpose of diplomacy is not to reach agreement with the other side but to achieve the end state one’s strategy requires.

Very occasionally, not talking is a form of negotiation. It can allow time to ripen circumstances conducive to concessions by one’s adversary, for example, by inciting quarrels between it and third parties, encouraging insurrection against it, or demonstrating one’s coercive capabilities against a third party. Or it can mean using talks to shelve issues, stall for time to strengthen one’s position, allow the situation to evolve in one’s favor, create a crisis that forces the other side to make decisions it would otherwise evade, or make the other side appear to have been so unreasonable as to leave no alternative to the use of force against it. Stalling for time can also mean entering talks but conceding only minor points, insisting that the major issues or principles be reserved until they can be resolved to one’s advantage.

Diplomatic intercourse should never be seen as a favor to the other side but as a convenience to one’s own. It is a means by which to convey one’s position directly to an adversary, to listen to its reasoning about its position on the issues in contention, to argue for changes in that reasoning, and to warn, cajole, and probe for evidence of willingness to concede specific points. Direct dialogue can lend gravitas and the credibility of body language to threats or carefully articulated offers to compromise in ways that written messages or communication through intermediaries cannot. It can help develop constructive ambiguity, repair bruised amour propre, facilitate cooperation on issues of common concern notwithstanding confrontation on other matters, develop personal relationships that ease the resolution of disputes or enable collusion once opportunities ripen for it, and provide a distraction for the media. Meetings with adversaries are the theater in which diplomacy best struts its stuff.

The major task of diplomacy is the management of relationships. In the new world disorder, these seem certain to be more fluid than they were in the last century. Transactionalism seems set to replace fixed friendships and animosities. The progressive debilitation of the (admittedly imperfect) protections of international law is leaving countries with no alternative to defending themselves as best they can with whatever weaponry they can build or acquire. Relationships embodying obligations are diminishing, freeing states to maneuver in accordance with their interests as they see them. There are likely to be many ententes, but progressively fewer alliances and protectorates. The rivalries in a multipolar state system are unlikely to support many client states – free riders on the ambitions of a single great power patron. Smaller states are likely to consider strategic promiscuity a safer course than bonding with a particular patron.

Where interests for a time coincide, nations will cooperate. Where and when they do not, they will not. This environment will penalize diplomatic immobility and incompetence and reward agility, flexibility, versatility, and responsiveness to change that underwrites adaptation, resilience, and innovative approaches to deal with new problems and opportunities.

Some international relationships are bound to be adversarial. Diplomacy must seek to forestall the transformation of adversaries into active enemies. That is, unless – as is rarely the case – overt hostility by one foreign party can stimulate rapprochement by a larger, more capable nation whose support would facilitate the pursuit of other, more important interests. It is usually in the national interest to inhibit the evolution of relations from skepticism to passive resistance to active opposition on issues. Such evolution can lead to broadly adversarial relations. Adversarial relations easily become broad hostility or outright enmity.

During the Cold War, the United States learned to rely on deterrence rather than diplomacy to address potentially explosive situations. This made sense in a world order with essentially fixed frontiers between two great blocs of states in which the United States enjoyed unmatched coercive power. But, in the context of disorder and fluid relations between states, it should not be the first resort of statecraft. Deterrence leaves the causes of potential conflict to evolve for the worse, stimulates arms races, invites countermeasures, generates “security dilemmas,” and often precludes cooperation on unrelated matters. Its effect is to prevent problems from exploding now but to leave them to explode later. Sometimes the passage of time erases or alleviates the danger that disputes might erupt in armed conflict. But it can also permit them to fester and enlarge their potential to produce catastrophe.

Delay makes sense when one’s power is growing relative to that of others. But, strong as the United States is and will remain, others are growing ever stronger. The balance of economic and military power is shifting away from America. In these circumstances, deferring problems for later resolution assures that when and if they come to a head, U.S. leverage will have weakened even as the outcome of conflict has become more uncertain.. Future American diplomacy must focus first on resolving disputes, not perpetuating them.

“Ignorance is the cause of fear,” Seneca reminds us. Fear generates suspicion. This easily becomes hostility. Mutual familiarity may not breed affection but it is the best cure for imagined security dilemmas, in which each side’s defensive responses to the other are seen as threatening and requiring an escalatory response.

Losing contact with the enemy on the battlefield risks surprise, flanking, or encirclement. Halting communication with a diplomatic opponent carries similar risks. The principle of statecraft embodied in what the Arabs call “Muʿāwiyah’s Hair” applies. The second Umayyad Caliph, Muʿāwiyah ibn Abī Sufyān, famously declared: “should there be but one hair between me and the others, I would not have it cut: for if they slacken it I would pull, and if they pull I would slacken it some.”

The dangers of substituting protracted deterrence for diplomacy are well illustrated in the current confrontation between the United States and the so-called Democratic People’s Republic of Korea. For sixty-five years, U.S. policy toward the north Korean regime has consisted of containment through ostracism, embargo, confrontation, and military shows of force. There is no gainsaying the despicable cruelty and thuggish belligerence of the Kim Dynasty. But at no point has the United States, which is unquestionably the stronger party, developed a strategy for coexistence with north Korea. There has been no American initiative to seek replacement of the 1953 armistice with a peace, despite the commitment of its signatories to do so. Instead, American policy has consistently projected the collapse of the north Korean regime or its conquest if large-scale combat on the Korean Peninsula recurs. The north Korean response has been a desperate drive to develop nuclear weapons to deter direct or indirect U.S. imposition of regime change. This effort has now achieved – or is nearing – success.

It has also produced a breakthrough for north Korean diplomacy in the form of American agreement to a summit meeting – something that Pyongyang has long sought. The mere fact of this meeting confirms the importance of the DPRK, its new status as the possessor of a nuclear deterrent, and – by implication – the legitimacy of both its state and its security concerns. President Trump agreed to this meeting on the basis of a south Korean read-out of a private conversation with Chairman Kim Jong-un to which no Americans were privy. So far as we know, Chairman Kim has not confirmed the president’s interpretation of his words directly or indirectly. They have not left the realm of hearsay.

Talking with adversaries is usually better than not talking, provided you know what you’re going to say and are confident you know what your counterpart can and cannot accept. Direct communication with north Korea’s leader on terms that convey respect for his power (but not his policies) may prove to be the key to a breakthrough. But it could also produce a catastrophe.

That is bound to be the case if the president simply repeats past American positions and does not address the fears that underlie north Korea policy. From Chairman Kim’s perspective, the United States has been saying: “if you don’t disarm yourself, we reserve the right to kill you, so give up your deterrent now, and we’ll see what we can work out.” Libya’s Colonel Qaddhafi took a chance on a similar offer and gave up his weapons programs. A few years later, he was memorialized by the U.S. secretary of state with the words, “we came. We saw. He died.” It will be very difficult to persuade Kim Jong-un to place his trust the United States.

Summits between adversaries are the diplomatic equivalent of single combat to decide battles between armies. Summits risk everything on the outcome of a single encounter. They add a direct clash between egos to a contest of interests. If they are well prepared, summits can ratify or finalize agreements and consolidate new relationships. But they can also exacerbate and further entrench confrontation. Given the stakes, summits are seldom, if ever, undertaken without extensive prior consultation and negotiation between subordinates. They proceed only when such dialogue has confirmed that an encounter between leaders has a high probability of producing a breakthrough rather than a setback in relations.

In some ways, despite the vast superiority of U.S. military power, President Trump will find himself at a disadvantage at any summit he may have with Mr. Kim. The United States has never had many experts on the DPRK. The past year has seen an exodus from the U.S. government of most of the American diplomats and officials with experience of direct contact with north Korean counterparts. By contrast, the north Korean side is staffed with officials who have spent decades dealing with Americans. The balance of expertise favors Pyongyang, not Washington. So does the balance of fervor. The issues for Chairman Kim and his country are existential. President Trump’s personal prestige may depend on the outcome of a meeting with Chairman Kim, but the future of the United States does not. As Mr. Trump often says, we will see what happens.

Whatever that is, American diplomats need to learn from it. The U.S. military has the healthy habit of after-action reviews to learn from what went right, what went wrong, and what might have been done better in an engagement. Sometimes what is learned is sufficiently important to be incorporated into doctrine. More commonly, it provides insights into how training can be improved. A reconstituted, more professional United States Foreign Service should institutionalize similar reviews of its own performance and make them as mandatory and routine as the inspection of management functions in embassies and other diplomatic organizations now is.

The constant review of experience is essential to extract and test the hypotheses that constitute the doctrine – the institutional memory and essential skill set – of any profession. The substance of diplomacy involves maneuvers between states and peoples. These are both intellectually fascinating and emotionally engaging. Much ink is spilt describing and analyzing them. Diplomats – even retired diplomats – easily become fixated on the issues with which diplomacy must grapple and fail to focus on the process and methodologies by which such grappling must be done. But such a focus is the sine qua non of mastery of the diplomatic arts. Such mastery will be essential for the recovery of American leadership once the current, self-inflicted weakening of the United States politico-economic role in world affairs is behind us.

Diplomacy is a universal skill, not the preserve of any particular nation or its history. There is a great deal to be learned from the ways in which the statesmen of other countries manage – or fail to manage – the issues that confront them. But the American experience alone is rich in examples of effective diplomatic tactics. It is time for Americans to start mining that experience for the lessons it contains and to incorporate what we learn in a teachable body of interrelated operational concepts. The raw materials to build such diplomatic doctrine are before us. We just need to exploit them.